1. Background of the Invention
This invention relates to a conveying roller assembly for conveying a sheetlike article, such as a strip of a film, a strip of a photosensitive member in a process camera or a developing unit, or paper sheets in a copying machine or a facsimile system.
A plurality of sheetlike article conveying apparatuses have been incorporated in these machines as they are being automated. In a prior art apparatus for conveying a sheetlike article, the sheetlike article is conveyed with a contact pressure applied by a plurality of pairs of conveying rollers, which are in linear contact with one another and are rotated in opposite directions. Such pairs of the conveying rollers are cylindrical in shape and have a uniform diameter longitudinally.
If such a cylindrical roller is not uniform in its diameter, the sheetlike article would skew or meander, and would not be conveyed smoothly. Therefore the rollers should be manufactured with a very high precision, thereby causing increase in the manufacturing cost. In addition, since the rollers have very smooth surfaces, the sheetlike article would slip between the rollers, and would not be conveyed reliably.
In a developing unit, dispersed components of a developer or fixing liquid tend to stick on the feed rollers, which requires to detach the conveying rollers from the developing unit so as to be cleaned. Since the individual cylindrical rollers are heavy, the whole roller unit would be heavy enough to require a large cleaning device and a lot of manpower for the cleaning work. In addition, the sheetlike article is sometimes wound around the circumferential surface of the roller, resulting in jamming.